Strategies towards highly luminescent quantum dots in glasses

Reference Presenter Authors
(Institution)
Abstract
10-027 Chao Liu Liu, C.(Wuhan University of Technology); Zhao, X.(Wuhan University of Technology); Han, J.(Wuhan University of Technology); Glasses containing semiconductor nanocrystals or quantum dots (QDs) have been studied for decades due to the particular optical and electronic properties of QDs induced by the quantum confinement effects. QDs embedded glasses have been utilized as color filters and saturable absorbers for pulsed light generation. However, emission related applications of these QDs embedded glasses are limited by low photoluminescence efficiency, arising from the unpassivated surface states of QDs in the amorphous matrix. Unlike the QDs synthesized through wet chemistry routes, manipulation of the surface states of QDs in the glass is difficult since the QDs are isolated by the glass network. In this talk, effects of glass structure modifiers (such as Na, Ca, Zn, etc.) and non-bridging oxygen on the structural and electronic properties of CdSe nanocrystals will be discussed. Approaches towards the surface passivation of QDs will be illustrated based on the oversaturation solubility of semiconductor compounds in the glass and controlled two-step sequential thermal annealing process. Core-graded shell structured CdSe QDs and sandwich structured CdS QDs were realized in the glasses. As a result, intense intrinsic emission from CdSe QDs and CdS QDs in the glasses was achieved and photoluminescence quantum yield as high as 50% was obtained. This strategy will also be useful for the preparation of other types of QDs in glasses.
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